Apoptosis in lupus SLE-N IV and non-lupus mesangiocapillary glomerulonephritis type I MCGN. I. A comparative study

Apoptosis plays an important role in the recovery from glomerulonephritis. Moreover, aberrant apoptosis seems to contribute to lupus nephritis. This study compared the intensity of apoptosis in lupus and non-lupus mesangiocapillary glomerulonephritis. We used an in situ cell death detection kit, POD, which detects single cell apoptosis in formalin-fixed renal tissue. Our material comprised 13 renal biopsy specimens from patients with lupus mesangiocapillary glomerulonephritis (SLE-N IV), 11 renal tissues from patients with non-lupus mesangiocapillary type I glomerulonephritis (MCGN) and 8 normal kidney samples. We checked the correlations between intraglomerular apoptotic cells and the total number of intraglomerular cells, the relationship between tubulointerstitial apoptotic cells and the relative interstitial cortical volume. The population of intraglomerular apoptotic cells was lower in tissues from SLE-N IV patients than patients with MCGN. In MCGN the intensity of apoptosis in glomeruli correlated significantly with the number of total glomerular cells. Tubulointerstitial apoptotic cells were infrequent in the kidney samples from patients with SLE-N IV and in the normal kidney. In the renal interstitium and tubuli the number of apoptotic cells did not correlate with the relative interstitial cortical volume in kidney tissue in patients with MCGN. In the biopsies from patients with SLE-N IV there was an inverse correlation between tubulointerstitial apoptotic cells and the relative interstitial cortical volume, so a low number of apoptotic tubulointerstitial cells was associated with fibrosis in the renal interstitium. The results illustrate the differences in the intensity of apoptosis in lupus and non-lupus glomerulonephritis. The low number of apoptotic cells in renal tissue from patients with SLE-N IV suggests regulation of apoptosis may be altered in the mechanisms of glomerular and tubulointerstitial damage in lupus nephritis, although the reduced apoptosis may simply be due to smaller numbers of cells in fibrotic areas.